This study investigates relationships between apoptotic cell death pathways, reactive oxygen species, and matrix metalloproteases in the mechanism of cerebral endothelial cell injury that results from exposure to elevated levels of homocysteine, a known risk factor for stroke. Homocysteine-induced injury in cultured mouse cerebral microvascular endothelial cells will be determined using cell death assays including lactate dehydrogenase release, and changes in expression of specific proteins of the apoptosis and cell-survival pathways will be measured using Western immunoblotting. Matrix metalloproteinase secretion will be additionally determined using gelatin zymography. Results will be compared between wild-type cells and those overexpressing superoxide dismutase-1, to study the involvement of oxygen radical scavenging in homocysteine-induced injury, as has been confirmed in the pathogenesis of cerebral ischemic damage. Such understanding can help elucidate mechanisms shared between ischemic and homocysteine-related injury, and might ultimately lead to novel strategies for stroke prevention and treatment through therapies targeted at points in the homocysteine injury pathway.